/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xpath.objects;

import org.w3c.dom.NodeList;

import wx.xml.xalan.xml.dtm.DTM;
import wx.xml.xalan.xml.dtm.DTMIterator;
import wx.xml.xalan.xml.utils.XMLString;
import wx.xml.xalan.xpath.Expression;
import wx.xml.xalan.xpath.ExpressionNode;
import wx.xml.xalan.xpath.XPathContext;
import wx.xml.xalan.xpath.axes.RTFIterator;

/**
 * This class represents an XPath result tree fragment object, and is capable of
 * converting the RTF to other types, such as a string.
 *
 * @xsl.usage general
 */
public class XRTreeFrag extends XObject implements Cloneable {
    static final long          serialVersionUID = -3201553822254911567L;
    protected    boolean       m_allowRelease   = false;
    private      DTMXRTreeFrag m_DTMXRTreeFrag;
    private      int           m_dtmRoot        = DTM.NULL;
    private XMLString m_xmlStr = null;

    /**
     * Create an XRTreeFrag Object.
     */
    public XRTreeFrag(int root, XPathContext xctxt, ExpressionNode parent) {
        super(null);
        exprSetParent(parent);
        initDTM(root, xctxt);
    }

    /**
     * Create an XRTreeFrag Object.
     */
    public XRTreeFrag(int root, XPathContext xctxt) {
        super(null);
        initDTM(root, xctxt);
    }

    /**
     * Create an XRTreeFrag Object.
     */
    public XRTreeFrag(Expression expr) {
        super(expr);
    }

    private final void initDTM(int root, XPathContext xctxt) {
        m_dtmRoot = root;
        final DTM dtm = xctxt.getDTM(root);
        if (dtm != null) {
            m_DTMXRTreeFrag = xctxt.getDTMXRTreeFrag(xctxt.getDTMIdentity(dtm));
        }
    }

    /**
     * Return a java object that's closest to the representation
     * that should be handed to an extension.
     *
     * @return The object that this class wraps
     */
    public Object object() {
        if (m_DTMXRTreeFrag.getXPathContext() != null)
            return new wx.xml.xalan.xml.dtm.ref.DTMNodeIterator((DTMIterator) (new wx.xml.xalan.xpath.NodeSetDTM(m_dtmRoot, m_DTMXRTreeFrag.getXPathContext().getDTMManager())));
        else
            return super.object();
    }

    /**
     * Specify if it's OK for detach to release the iterator for reuse.
     *
     * @param allowRelease true if it is OK for detach to release this iterator
     *                     for pooling.
     */
    public void allowDetachToRelease(boolean allowRelease) {
        m_allowRelease = allowRelease;
    }

    /**
     * Detaches the <code>DTMIterator</code> from the set which it iterated
     * over, releasing any computational resources and placing the iterator
     * in the INVALID state. After <code>detach</code> has been invoked,
     * calls to <code>nextNode</code> or <code>previousNode</code> will
     * raise a runtime exception.
     * <p>
     * In general, detach should only be called once on the object.
     */
    public void detach() {
        if (m_allowRelease) {
            m_DTMXRTreeFrag.destruct();
            setObject(null);
        }
    }

    /**
     * Tell what kind of class this is.
     *
     * @return type CLASS_RTREEFRAG
     */
    public int getType() {
        return CLASS_RTREEFRAG;
    }

    /**
     * Given a request type, return the equivalent string.
     * For diagnostic purposes.
     *
     * @return type string "#RTREEFRAG"
     */
    public String getTypeString() {
        return "#RTREEFRAG";
    }

    /**
     * Cast result object to a number.
     *
     * @return The result tree fragment as a number or NaN
     */
    public double num()
        throws javax.xml.transform.TransformerException {

        XMLString s = xstr();

        return s.toDouble();
    }

    /**
     * Cast result object to a boolean.  This always returns true for a RTreeFrag
     * because it is treated like a node-set with a single root node.
     *
     * @return true
     */
    public boolean bool() {
        return true;
    }

    /**
     * Cast result object to an XMLString.
     *
     * @return The document fragment node data or the empty string.
     */
    public XMLString xstr() {
        if (null == m_xmlStr)
            m_xmlStr = m_DTMXRTreeFrag.getDTM().getStringValue(m_dtmRoot);

        return m_xmlStr;
    }

    /**
     * Cast result object to a string.
     *
     * @return The string this wraps or the empty string if null
     */
    public void appendToFsb(wx.xml.xalan.xml.utils.FastStringBuffer fsb) {
        XString xstring = (XString) xstr();
        xstring.appendToFsb(fsb);
    }


    /**
     * Cast result object to a string.
     *
     * @return The document fragment node data or the empty string.
     */
    public String str() {
        String str = m_DTMXRTreeFrag.getDTM().getStringValue(m_dtmRoot).toString();

        return (null == str) ? "" : str;
    }

    /**
     * Cast result object to a result tree fragment.
     *
     * @return The document fragment this wraps
     */
    public int rtf() {
        return m_dtmRoot;
    }

    /**
     * Cast result object to a DTMIterator.
     * dml - modified to return an RTFIterator for
     * benefit of EXSLT object-type function in
     * {@link wx.xml.xalan.xalan.lib.ExsltCommon}.
     *
     * @return The document fragment as a DTMIterator
     */
    public DTMIterator asNodeIterator() {
        return new RTFIterator(m_dtmRoot, m_DTMXRTreeFrag.getXPathContext().getDTMManager());
    }

    /**
     * Cast result object to a nodelist. (special function).
     *
     * @return The document fragment as a nodelist
     */
    public NodeList convertToNodeset() {

        if (m_obj instanceof NodeList)
            return (NodeList) m_obj;
        else
            return new wx.xml.xalan.xml.dtm.ref.DTMNodeList(asNodeIterator());
    }

    /**
     * Tell if two objects are functionally equal.
     *
     * @param obj2 Object to compare this to
     * @return True if the two objects are equal
     * @throws javax.xml.transform.TransformerException
     */
    public boolean equals(XObject obj2) {

        try {
            if (XObject.CLASS_NODESET == obj2.getType()) {

                // In order to handle the 'all' semantics of
                // nodeset comparisons, we always call the
                // nodeset function.
                return obj2.equals(this);
            } else if (XObject.CLASS_BOOLEAN == obj2.getType()) {
                return bool() == obj2.bool();
            } else if (XObject.CLASS_NUMBER == obj2.getType()) {
                return num() == obj2.num();
            } else if (XObject.CLASS_NODESET == obj2.getType()) {
                return xstr().equals(obj2.xstr());
            } else if (XObject.CLASS_STRING == obj2.getType()) {
                return xstr().equals(obj2.xstr());
            } else if (XObject.CLASS_RTREEFRAG == obj2.getType()) {

                // Probably not so good.  Think about this.
                return xstr().equals(obj2.xstr());
            } else {
                return super.equals(obj2);
            }
        } catch (javax.xml.transform.TransformerException te) {
            throw new wx.xml.xalan.xml.utils.WrappedRuntimeException(te);
        }
    }

}
